I spent part of the weekend chatting with a friend in Cambridge
who used to be science editor at The Independent
and now edits Scientific Computing World.
During those conversations,
I realized that there are three graphs I'd really like to see:

Ask the managers of high-performance computing centers what fraction of their budget they spent on hardware, software, and training,
and what fractions they would like to spend.
My prediction is:

Measure how much computing power all of the scientists at a university (not just those with HPC accounts) use during a year.
My prediction is:

Classify all the support requests received by HPC center staff according to technical complexity,
and see how that changes after something like a two-day Software Carpentry workshop.
My prediction is:

The first tells us how much political interference
(i.e., administrators' desire for photo opportunities)
skews computing priorities.
The second will show the mis-match between where computing money is spent
and what most scientists actually do,
while the third will show that training doesn't just help scientists directly:
it also improves the ROI of highly-skilled support staff.